Interannual variability of air-sea O-2 fluxes and the determination of CO2 sinks using atmospheric O-2/N-2.

(McKinley, GA and Follows, MJ and Marshall, J and Fan, SM), GEOPHYSICAL RESEARCH LETTERS, vol. 30, no. 3, 2003.

Abstract

Motivated by the use of atmospheric O-2/N-2 to determine CO2 sinks under the assumption of negligible interannual variability in air-sea O-2 fluxes, we examine interannual fluctuations of the global air-sea flux of O-2 during the period 1980-1998 using a global ocean circulation and biogeochemistry model along with an atmospheric transport model. It is found that both the El Nino/Southern Oscillation (ENSO) cycle and wintertime convection in the North Atlantic are primary drivers of global air-sea oxygen flux interannual variability. Model estimated extremes of O-2 flux variability are -70/+100 x 10 12 mol/yr (Tmol/yr), where positive fluxes are to the atmosphere. O-2/N-2 variability could cause an up to +/-1.0 PgC/yr error in estimates of interannual variability in land and ocean CO2 sinks derived from atmospheric O-2/N-2 observations.

doi = 10.1029/2002GL016044